The objective of the research are to test in a quantitative mathematical way hypothesis concerning retinal neuronal interconnections. These hypotheses concern interconnections which give rise to neuronal transformations of lateral inhibition, summation, and spatial frequency (alternately, wavelength) filtering and selectivity. Experiments are proposed which make use of time modulated light intensity stimuli of appropriate spatial configuration and color, intracellular micropipette recordings in a vertebrate retina, extra- and intracellular recordings in an invertebrate retina, and computer implemented methods of processing these recordings. In most cases in the proposed research the experiments are designed to test quantitative mathematical hypotheses. These concern primarily the dependence of intracellular potential response of retinal cells on both time and spatial frequency content of the light intensity stimulus. A specific linear mathematical model of lateral inhibition in the outer plexiform layer of Necturus is proposed layer is proposed, and then methods of nonlinear mathematical modeling and experimentation are outlined. These vertebrate retina experiments concern directly time and time frequency dependence, but have implications for spatial frequency dependence. In the receptor layer (retinular cells) of the retina of the locust experiments are proposed to test a mathematical model, part of which has predicted the dependence of higher order retinal cells, (descending movement detector, the DMD) on spatial frequency content of the light intensity stimulus. The purpose of these experiments is to assess receptor layer contributions to this dependence. Then experiments are proposed to test in the descending movement detector (DMD) the existence of spatial frequency channel selectivity as a possible basis for the known target/background discrimination capabilities of this unit. This topic can be further explored by appropriately adjusting the color spectrum of the stimulus (and such experiments are next proposed.) To understand better the neuronal transformations between the receptor layer and the DMD, experiments designed to elucidate lamina function are then proposed.